Following a trend that emerged at Strategies in Light, SemiLEDs has joined the list of companies to offer flip-chip LEDs in minimal packages for integration into lamps or luminaires, or larger LED packages.
SemiLEDs has announced the EF-B40, blue flip-chip LED family designed for integration into chip-on-board (COB) packages or for direct integration into lamps and luminaires that use a surface-mount assembly process. The SemiLEDs Enhanced FlipChip (EF) design simplifies the manufacturing process at the LED and component level and has the potential to lower the cost of solid-state lighting (SSL) products. The company also announced the white EC-W1414 LED based on the new flip-chip die.
The SemiLEDs blue LED is the latest in a large number of flip-chip LEDs announced this year. Samsung kicked off the trend at Strategies in Light and has delivered both mid- and high-power LEDs in a flip-chip or chip-scale package (CSP). At Light+Building the trend continued with the likes of Toshiba, Epistar, and Lextar announcing flip-chip devices. Philips Lumileds had pioneered the technology back in 2013.
The new SemiLEDs EF-B40 is a blue LED, meaning that phosphor will be required to produce white light. The phosphor could come with the LED arrayed in a COB that is coated with phosphor, in a remote- or cold-phosphor light engine, or perhaps with phosphor applied directly to the light-emitting surface of the individual LED.
SemiLEDs was the first of the flip-chip purveyors to specifically mention COB applications, driven perhaps by the rising popularity of the larger LEDs that can be more simply integrated into lamps and luiminaires. "SemiLEDs' unique flip-chip approach combines a sapphire front surface and proprietary back side architecture that provides the electrical contacts exclusively on the bottom of the chip, making it fully compatible with COB surface-mount processes," said Mark Tuttle, general manager for SemiLEDs Optoelectronics Co. "Eliminating wire-bonds also lowers the profile of the chips, and allows them to be placed more closely together, which results in higher lumen-density and reduces the complexity of the optics. The EF series is an ideal platform for COB assemblies, or really for any approach that calls for either secondary optic design or high-density mounting."
SemiLEDS will offer the blue LED at wavelengths ranging from 455–460-nm, the typical range for blue-pump LEDs. With phosphor applied, the LEDs can deliver up to 300 lm from 1A of drive current. The flat light-emitting surface delivers a 140° viewing angle.
White CSP LED
SemiLEDs also announced the white ReadyMount Enhanced CSP (EC) series of LEDs that are based on the blue pump. The 1.4×1.4-mm EC-W1414 series uses the company's ReadyWhite phoshor technology. The CSP device will still require surface-mount assembly and can serve in LED arrays, LED light engines, or lamps and luminaires.
"Our CSP brings all the benefits of SemiLEDs' rugged EF Series FlipChip architecture to an extremely compact emitter, which is simple to integrate using standard tape and reel surface-mount manufacturing," said Tuttle. "This innovation reduces final component cost up to 50%, with a packaging cost reduction of up to 80% over conventional packaging. EC Series products, such as the EC-W1414, enable system integrators and luminaire manufacturers a direct path to a highly cost-effective solution on a per-lumen basis now, with additional viewing angles and die sizes under development."
SemiLEDs will offer the 3W white CSP LEDs over a range of 2700K to 10,000K CCT and with the option of a 90-minimum CRI. The phosphor is flatly applied to the sapphire light-emitting surface and the white LED produces the same wide viewing angle as the blue pump.